Nausea is a reaction to a number of causes that include overeating, infection, or irritation of the throat or stomach lining. Persistent or recurrent nausea and vomiting should be checked by a doctor.
Persistent, unexplained, or recurring nausea and vomiting can be symptoms of a variety of illnesses. It can be caused by simply overeating or drinking too much alcohol. It can be due to stress, certain medications, or illness. For example, people who are given morphine or other opioid medications for pain relief after surgery sometimes feel nauseated by the drug. Such poisonous substances as arsenic and other heavy metals cause nausea and vomiting. Morning sickness is a consequence of pregnancy-related hormone changes. Motion sickness can be induced by traveling in a vehicle, plane, or on a boat. Many patients experience nausea after eating spoiled food or foods to which they are allergic. Patients who suffer migraine headache often experience nausea. Cancer patients on chemotherapy are often nauseated. Gallstones, gastroenteritis, and stomach ulcer may cause nausea and vomiting. Such infectious illnesses as dengue fever and severe acute respiratory syndrome (SARS) may be accompanied by nausea and vomiting.
Vitamin K is a fat-soluble vitamin. The recommended dietary allowance (RDA) for vitamin K is 80 mg/day for the adult man, 65 mg/day for the adult woman, and 5 mg/day for the newborn infant. The vitamin K present in plant foods is called phylloquinone; while the form of the vitamin present in animal foods is called menaquinone. Both of these vitamins are absorbed from the diet and converted to an active form called dihydrovitamin K.
Vitamin K plays an important role in blood clotting. Without the vitamin, even a small cut would cause continuous bleeding in the body, and death. Blood clotting is a process that begins automatically when any injury produces a tear in a blood vessel. The process of blood clotting involves a collection of molecules, which circulate continuously through the bloodstream. When an injury occurs, these molecules rapidly assemble and form the blood clot. The clotting factors are proteins, and include proteins called Factor II, Factor VII, Factor IX, and Factor X. Factor II is also called prothrombin. These proteins require vitamin K for their synthesis in the body. The blood-clotting process also requires a dozen other proteins that do not need vitamin K for their synthesis.